1. Field of the Invention
This invention relates to a vehicular power system.
2. Description of the Related Art
A method of inserting a mechanical key into a key cylinder and turning the key to start the engine has been used as an engine start operation for a vehicle. In recent years, however, a push start system for starting the engine by a pressing operation or a touching operation of a push type switch (engine switch) has been adopted.
Incidentally, the mechanical key can be turned in two directions, right and left, one being a direction for starting the engine and the other for stopping the engine. These rotational angles allow to freely switch between electricity supply states (OFF state, ACC state). In the push start system, on the other hand, only one operation of pressing the engine switch is performed, and the number of pressing operations makes a transit from an electricity supply state to the other. Furthermore, the information on the position of the shift lever or on whether the brake pedal is pressed or not generally determines a target electricity supply state to transit (see FIG. 4 of Japanese Patent Application Publication No. 2006-77592 (JP-A-2006-77592)).
However, in this general push start system, even if the engine switch is pressed during an ON state (engine starting state or IG-ON state) when the shift lever is in a position other than a P range, the vehicle is not in the OFF state for antitheft purposes but in the ACC state, as described in FIG. 4 of the above JP-A-2006-77592. Therefore, when a user wishes to switch the vehicle from the ACC state to the OFF state, the user needs to shift the shift lever to the P range, press the engine switch to bring the vehicle to the ON state, and then press the engine switch again (in other words, the user needs to shift the shift lever to the P range and press the engine switch twice). Such operations are difficult for the user to understand but have room for improvement in point of convenience.